An SH0 lithium niobate trans-impedance chirp compressor with high voltage gain

Abstract

We present a new type of acoustic devices that, for the first time, can simultaneously perform chirp compression and impedance transformation to achieve passive voltage amplification with a gain of 12. The device consists of an acoustic dispersive delay line (DDL) based on shear-horizontal waves (SH0) in lithium niobate (LiNbO3). SH0 waves are employed due to their demonstrated high electromechanical coupling (k2) of 39%, low propagation loss, and a slow phase velocity of 3700 m/s. As a result of these desirable features, the fabricated device demonstrates a large fractional bandwidth (FBW) of 50%, a low insertion loss (IL), a high processing gain (TB) of 76, and a compact size of 1.57 by 0.23 mm. In addition to the compression, the device harnesses an asymmetrical transduction scheme to provide a compounding voltage gain from impedance transformation. Consequently, it results in a much higher voltage at the device output, which can be exploited to attain a higher sensitivity for wake-up radio receivers.